Optimizing Crumb Rubber Modifiers (CRM) and Reclaimed Asphalt Pavements (RAP) in Typical Ontario Hot Mix Asphalt

摘要

Genuine sustainability begins with reduction enhanced by a culture of reusing and recycling waste materials. Rather than destroy or discard scrap rubber tires and Reclaimed Asphalt Pavement (RAP) in landfills, both materials have been successfully engineered to improve the mechanical properties of Hot Mix Asphalt (HMA) mixtures. These waste materials are used by select transportation agencies in Canada. However, in comparison to current supply, the percentage used in Ontario is rather conservative. The objective of this paper is to evaluate the use of higher percentages of Crumb Rubber Modifiers (CRM), a by-product of scrap rubber tires, and RAP in typical Ontario HMA. This paper uses the Superpave? mix designs system to characterize and compare the low-temperature cracking performance of RAP and CRM in HMA. The effects of the different binder grades, RAP content, and CRM incorporation methods on the fracture parameters of the HMA mixtures are examined. The influence of mix volumetric, aggregate gradation, binder aging, and laboratory compaction method were also observed. Test results demonstrate that the wet-process of incorporating CRM in HMA is effective, and that typical Ontario HMA mixtures incorporating high RAP and CRM percentag